FORAMINIFERA OF NORTH PACIFIC OCEAN. 



95 



VIRGULINA TEXTURATA H. B. Brady. 



Virgulina texturata H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, 

 p. 115, pi. 52, figs. 6, a, b. — Egger, Abh. kon. bay. Akad. Wiss. Miinchen, 

 CI. ii, vol. 18, 1893, p. 292, pi. 8, fig. 99. 



Description. — Test elongate, subcylindrical, gradually tapering to 

 the subacute apical end, somewhat compressed; chambers numerous, 

 inflated, about as broad as high, the sutures distinctly depressed; wall 

 calcareous, smooth and polished; aperture elongate, loop-shaped; 

 color white. 



Length 1.0-1.3 mm. 



Distribution. — Although not previously recorded from the North 

 Pacific, this species has occurred at three stations, 

 Albatross station H2902, in 1,783 fathoms, and Nero 

 stations 166 and 170, in 1,850 and 1,990 fathoms. 



The specimens from Nero station 166 were very 

 smooth and somewhat different from the typical ones 

 found at the other stations. 



Subfamily 4. CASSIDTJLIIvriN'JK. 



This subfamily includes forms which are peculiarly 

 constructed in that there is a combination of two dis- 

 tinct modes of growth. One of these, so usual in this 

 family, is the biserial, which is here combined with a 

 spiral or volute method. The combination of the two 

 makes a complex test. 



Two genera are common in the North Pacific, 

 Cassidulina and Ehrenbergina, both of which are 

 represented by more than one species. 



Genus CASSIDULINA, d'Orbigny, 1826. 



Cassidulina d'Orbigny (type, C. laevigata d'Orbigny), Ann. 

 Sci. Nat., vol. 7, 1826, p. 282.— H. B. Brady, Rep. Voy. 



Challenger, Zoology, vol. 9, 1884, p. 427. 



Description. — Test coiled, at least the earlier por- 

 tion, and the chambers biserialfy arranged on the 

 sides of the axis of coiling; wall calcareous, perfo- 

 rate, usually smooth; the chambers numerous, with 

 distinct sutures; aperture loop-like, variously modified in the dif- 

 ferent species. 



The most lucid description of the arrangement of the chambers in 

 this genus is that given by Brady, as follows: "The arrangement of 

 the test in Cassidulina is in some respects more complex than that of 

 any other t}-pe of Foraminifera, inasmuch as it combines two dis- 

 tinct modes of growth, the biserial and the convoluted. This may 



Fig. 149.— Virgu- 

 lina TEXTURATA. 

 X 35. a, FRONT 

 view; b, APER- 

 TVRAL VIEW. 



